As a vehicle starts from rest and accelerates on a split-μ surface, a drive slip control system usually intervenes in operation of the vehicle in such a way that when a defined slip threshold is exceeded the wheel located on the slick side of the road surface (low-μ wheel) is braked by braking intervention, and optionally the engine torque is reduced.
In the braking intervention, the braking torque exerted by the brake of the low-μ wheel is transferred via the differential to the other wheel that is not yet slipping. This transferred drive torque can in turn cause the wheel that is not yet slipping (high-μ wheel) also to be begin slipping; as a result, the stability and in particular lateral stability of the vehicle, as well as traction at the wheel which is still adhering, are lost, and critical driving situations can occur.
To prevent detachment of the high-μ wheel on a preventive basis, in previously known drive slip control systems the braking pressure at the low-μ wheel, and thus the drive torque at the high-μ wheel, are modified (modulated) only very carefully. The acceleration behavior of the vehicle thereby suffers, especially when starting from rest and accelerating on slopes.
If slippage of the high-μ wheel nevertheless occurs, existing drive slip control systems are not capable of intercepting the breakaway of the high-μ wheel sufficiently quickly, and rapidly re-establishing vehicle stability.